Electronic distributor



Patented Mar. 8, 1938 UNITED STATES PATENT OFFICE Patent No. 2,057,773, dated October 20,

1936. Divided and this application October 14, 1936, Serial No. 105,461

6 Claims.

My invention relates to electronic distributors useful in signalling systems, and more particularly, relates to the application of an electron beam distributor to high speed printing telegraphy.

This invention is a division of the parent application Serial No. 52,871, filed December 4,

1935, which matured into Patent No. 2,057,773`

on October 20, 1936.

Modern high speed printing telegraph systems operate with a Baudet or ve unit code. A continuous tape is successively punched with a predetermined combination of holes for each character. It is the practice to pass the tape through apparatus having ve mechanical feelers which in turn operate contactors connected to contact plates on a mechanical distributor. The mechanical distributor, as is well known in the telegraph art, comprises a rotating arm for successively contacting the contact plates to transmit coded impulses in succession. The operation of mechanical distributors materially limits the speed of transmission of printing telegraph signals.

It is the main object of my present invention to eliminate the mechanical distributor and substitute therefor .an electronic distributor. The electron beam of 'a cathode ray tube is ma-de to scan a plurality of metallic plates or targets corresponding to the individual contacts of a mechanical distributor. The substitution of an inertialess selector for the mechanical'selector in a distributor makes possible accurate transmission of telegraphy signals at much higher speeds than heretofore possible. A receiver is arranged having an electronic distributor similar to that of the transmitter and selects the transmitted code signals to operate standard telegraph printing apparatus.

It is accordingly an object ofiy my invention to provide a novel high speed signalling system.

Another object of my invention is to provide -a novel electronic distributor to replace the me chanical distributor in printing telegraphy systems.

Still another object of my invention is to pro vide a novel means for synchronizing the operation of transmitter and receiver electronic distributors in signalling systems.

A further object of my invention is to provide novel methods of and means for high speed transmission and translation of coded signals successively punched in a perfor-ated message tape.

Theseand other objects of my invention will become apparent in the following description in connection with the drawing, in which:

Figure 1 is a schematic illustration of one embodiment of a transmitting telegraphy system employing an electronic distributor in accordance with my invention. y

Figure 2 is a schematic illustration of a receiver for translating the printing telegraphy signals transmitted according to Figure 1.

In carrying out my invention, I employ an electron beam I0 produced in a highly evacuated Vessel II. The generation of the electron beam is familiar to those skilled in the electronic art and is schematically shown in Figure 1. The cathode I2 is heated by the heater I3 which is 15 connected to suitable battery supply. The rst anode I4 concentrates the emitted electrons into an electron beam. Thehigh voltage anode I5 accelerates the electrons of the beam I0 which passes between the electrostatic deecting plates I6, I'I, I3 an-d I9 and on to the opposite end 20 of the vessel I I.

A high voltage direct current potential source 2l supplies the operating potentials for the electrodes of the cathode ray tube I I. A potentiom- `eter 22 is connected across the battery 2|. The

second or high voltage anode I5 is connected to the positive side 23 of the potentiometer 22 which point is' connected to ground in my preferred` embodiment. The first anode I4 is connected to 30 a suitable intermediate potential by tap 24. The control grid 25 is negatively biased with respect to the cathode AI2 by a suitable tap 25 of the potentiometer 22. Delecting plates I6 and i8 are connected to the grounded high potential point 23 to assume the same potential as the anode I5. The plates Il and I9 are connected to ground through high resistanes 2l and 28 so that the electrostatic deflecting plates and the anode l5 have a common static potential which lis at ground potential, an operating expedient commonly employed.

On the back face 29 of the tube Il, l arrange a plurality of metallic plates or targets 29 Within the tube. As illustrated in Figure l, these plates 29 are preferably spaced around a circle within the tube iI and have connections projecting through the tube at points 3l). Five of the metallic electro-des 29 yare connected to corresponding contactors 3l of a selector mechanism 32. 5G In modern printing telegraphy, a message tape is employed which has a succession of groups of holes punched according to a predetermined code. The commonly used Baudot code, for example, employs group combinations of five units to correspond to individual letters or symbols. The punched tope is passed through a selector mech anism which has five leclerc which coact with the tape and operate contactors 3| as is well known in the art. I have schematically illustrated'such a selector mechanism at 32.

The contacts of the contactors 3| are connected in parallel across the input circuit 33 of a thermionic amplifier stage 34. The output 35 of the amplifier 34 is connected to a modulator 36 for modulating a radio frequency carrier produced by the radio frequency oscillator 3l connected to the radio frequency amplifier 38 to be transmitted for radio transmission by the antenna 39. y

A local oscillator 40 is connected to the electrostatic deecting plates and I9 through a rotator circuit 4I comprising a condenser 42 and resistance 43 connected as shown. The impedance of the condenser 42 is adjusted to be substantially equal to the resistance 43 at the frequency of the local oscillator 40. The electron beam I0 will be moved in a circular path as is Well known in the art. The diameter of this circular path 44 at the end 20 of the tube il depende upon the voltage output of the oscillator 4B which is adjusted so that the diameter of the path 44 coincides with the mean diameter of the circularly arranged plates 29. There is thus provided means for cyclically scanning the electrodes 29 at a predetermined rate dependent upon the oscillator to frequency.

When the electron beam I@ impinges on s. target 29, the electrons will be conducted to ground through its corresponding contactor Sil if it is not actuated by its selector feeler, but connects to the lower contact. However, if a feeler oi the selector mechanism 32 at that time projects through a hole in. the perforated tape, an arm of the corresponding contactor, for example, Sia, `will be moved to connect to its upper contact point 45 and the electrons of beam lil impinging on the corresponding target 29a will be conductively connected to the grid lil of the-thermionic amplier 36|. The electrons of the beam i0 are conductively connected to ground since the high potential side of its accelerating battery source 2| is connected to ground. The electrons of the beam i0 accordingly pass to ground through the input circuit or grid resistor 33. The electrons owing through the grid resistor 33 produce a potential change upon the grid 36. A corresponding impulse is transmitted through the amplifier' 36| to its output 35. Accordingly, while the electron beam Ill is passing over an electrode 29 having its corresponding contacter 3| actuated by a selector feeler projecting into a hole in the perforated tape, electrons will be conducted to the input circuit of the amplier 3d and produce a pulse or signal therethrough. This pulse or signal is introduced to the modulator 36 for radio transmission as described.

The operation of the electronic distributor according to my invention therefor is to cause an electron beam @El to successively scan a plurality of metallic target electrodes 29 arranged at the far end of the evacuated envelope il The electrodes 29 are connected to individual contactors iii of a selector mechanism 32 of a perforated tape tclegraphy system. Each contacter 3i and its corresponding electrode 29 correspond to a predetermined component of the five unit code of the perforated tape. With each symbol group punched in the tape, a corresponding arrangearmeno ment of contactors 3| will be actuated to their upper contacts during the transmission ol the code group. The frequency of the oscillator 40 is adjusted so that it successively scans all the electrodes 29 once for each code group advanced through the selector vmechanism 32. Each contactor 3| actuated by a hole in the perforated tape conductively connects its corresponding electrode 29 to the grid 4'6 of the amplifier 34, and a signal pulse will be produced by the amplifier 34 when the electron beam IIJ passes over this target 9.` Accordingly, a succession of signal pulses is transmitted corresponding to the code group on the perforated tape being presented to the mechanical feelers in the selector mechanism.

The selecting mechanism feeds the perforated tape at a predetermined rate in accordance with the frequency of scanning of the electrodes 29 and each code group is retained by the selector pins during the execution of each cycle of scanning. 'I'he electron beam will therefore be conductively connected to the grid 46 of the ampli- Iier 34 as it successively scans the electrodes 29 in accordance with the code group being transmitted.

The advancement of the perforated message tape, through the-selector mechanism 32 is synchronized with the scanning movements of the electron beam i0 over the targets 29. The tape is retained in the selector mechanism during the scanning operation of a code group and is advanced to the next code group,A at the end of each cycle. The actuating means for the stepping of the tape through the selector mechanism is preferably an electro-magnetically operated pawl and ratchet arrangement schematically shown as 32a. I provide a sixth target electrode 29o, which is connected directly to the stepping mechanism 32a. A signal amplifier is included in the electro-magnetic unit 32a to sufficiently amplify the impulse to operate the mechanical stepping means. The electrode 29h sets off the five signal targets 29 into one group. At the end of a code group transmission, therefore, the electrode 29h is impinged by beam i0 and the electromagnetically operated stepping mechanism automatically advances the message tape to the next code group to be transmitted. The cycle is then repeated. The rate of transmission of the code groups is accordingly predetermined by adjusting the frequency of the oscillator 4U, the number of groups transmitted per second being equal to the generated cycles per second of the oscillater si).

The target 29h is also connected to the input circuit 33 of the signal impulse amplifier 34 through a unidirectional conduction device 48. dd may be a buffer stage of thermionic amplication, or a rectier. The unidirectional conductor d3 is used to transmit an electro-n beam impulse on target 29h to the signal ampliller 34, but to prevent any signal impulses from other targets reaching the stepping amplifier 32a. The stepping mechanism 32a will therefore be actuated only by the impulses on target 29h for proper action thereof. The impression of an impulse of target 29h upon the signal amplifier 34 results in the transmission, at the end of each cycle, an impulse to be utilized at the receiver as a printing and synchronizing impulse. The function of the printing and synchronizing impulse Will be described hereinafter in connection with, the receiver printing mechanism.

in Figure 2, I have illustrated electronic reaimee-e ceiving apparatus for use in conjunction with the transmitter. The receiving antenna 49 is connected to the radio receiver 49' which detects and ampliiies the telegraphy signals.

The deiiecting plates 65 and 56 are directly connected to ground potential. The second anode 51 is also connected to ground potential as is the positive terminal of the high voltage direct current source B through transformer 1I secondary. The operating potential of the iirst anode 6I is adjusted with the tap 62 of the potentiometer 6i).` Resistors 63 and 64 having high resistance, connect the deflecting plates 53 and 54 tov ground static potential.

The receiver electronic distributor 65 is of similar construction to that of the transmitter of Figure 1. An electronic beam 66 is produced and caused to scan a plurality of metallic electrodes or targets 61 arranged in a circular path on the interior of the back wall of the evacuated envelope. The targets 61 are individually J connected to the input of amplifiers 69 at the'outputs of which are connected relays 1|l. There are six relays 10 which are used to operate a local printing telegraph. The output lof the receiver 49 is connected to a transformer 1i the output of which controls the operation of the electronic distributor 65. The grid 12 bias po- ,f tential is adjusted to a suitable negative value by the potentiometer 13 connected across the grid biasing battery 14.

When the electron beam 66 mpinges upon a target 61, a pulse is introduced to the input of the corresponding amplifier 69. The production of the pulse by the electron beam 66 at the ampliiier 69 input is the same as the production of the signal impulse introduced at the grid 46 of the amplifier 34 of Figure 1 described herein above. The ampliiiers 69 are made sufiiciently sensitive to suitably energize the corresponding relays 10 for actuating the local printing mechanism.

There are six target electrodes ,61. The synchronizng electrode 61h corresponds to the electrode 29h of Figure 1. A local oscillator 11 generates sinusoidal waves. In operation the frequency of oscillator 11 equals that of transmitter oscillator 40. 'The output of oscillator 11 is introduced to the rotator circuit 52 connecting across the defiecting plates 53 and 54 to produce the rotation of beam 66 in the` circular path 15 in a manner similar to rotator 4i. The local synchronizing impulse is obtained when the electron beam 66 mpinges on the electrode 61h. The electron impulse is introduced to the pulse amplifier 18, the output of which is connected to the oscillator 11. The frequency of the local oscil lator 11 is adjusted close to that of transmitter oscillator 4D. The synchronizing impulses introduced by amplier 18 to ,the oscillator 11 in' terlock or synchronize it with the transmitting oscillator lill to cause it to generate the same frequency as the oscillator 4U of the transmitter. The interlocking arrangement for synchronization of the two remote oscillators is familiar to those skilled in the communications art and is not considered necessary to describe in the pres ent disclosure.

The phase of the scanning signal of the impulse excited interlocked oscillator is adjusted by Well known phases shifting means, schematically indicatedrat 16, to cause the electron beam 66 to pass over predetermined targets 61 in synchronization with the corresponding targets at the transmitter in order to maintain the code combinations for the printing mechanism. Therefore. when the electron beam l0 of 'the transmitter impinges on the electrode 29a, the receiver electron beam 66 will impinge upon the corresponding electrode 61a to actuate the printing relay 16a, in proper sequence. Once the beam 66 is adjusted in proper phase relation with the transmitted impulses, the electronic distributor according to my invention will continue to be in synchronism with the transmitter and operate to selectively print the letters-or symbols which are selected by the mechanism 32 of the transmitter according to the coded punchings in the perforated tape passing therethrough.

The operating potentials of theelectrodes are adjusted so that the beam 66 normally traverses a circular path sufficiently small in diameter to avoid the targets 15, and rotating in phase synchronism with the transmitter beam I0. The output of the receiver 49' is connected to the primary of transformer 1I, the secondary of which is connected in series with the high potential terminal 19 of the high voltage source 58 and ground. The signal impulses, alter the deectional sensitivity of the electron beam. The signals are polarized so that during a signal impulse, the beam 66 is made more sensitive to the rotator voltage, and reaches the indicated path to move across the corresponding targets 61. During no signal impulse, the electron beam 66 rotates in a path smaller in diameter than 15 and does not mpinge on the electrodes 61, producing no actuation of corresponding relays 10.

The signal impulses transmitted by the system according .to Figure 1 are detected and amplified by the receiver 49 of Figure 2 and impressed upon the electrodes of the electronic distributor 65 to alter the deectional sensitivity of the beam 66. A signal impulse permits the beam 66 to travel in the normal path 15, the diameter of which is determined by the voltage produced by the local oscillator 11. There is one synchronizing impulse per code group or cycle of operations, which impulse is received by the electrode 61D,

land amplied by pulse amplifier unit 18. The

amplified pulse is used to interlock or synchronize the local oscillator 11 with the transmitter oscillator 4|). Whenever a signal impulse is impressed on the apparatus, the beam 66 is caused to impinge on the proper target 61 and a signal impulse will be impressed upon the input of the corresponding amplifier unit 69. A translator relay 16 is connected at the output of each amplifier unit 69. When no signal impulse is received, the beam passes around or misses the target 61 corresponding to the relative position of the beam 66 and no impulse is impressed upon its associated amplifier 69, leaving the corresponding relay 10 unactuated. A succession of combinations of five on and off signals Will set up the predetermined letter or character selected by the transmitter selector mechanism 32 upon the local printing apparatus.

The printing impulse transmitted at the end of each code group as hereinabove described, corresponds to the position of target 61h. Accordingly, an impulse will be impressed through target 61h upon the amplifier 69D to actuate a printing impulse relay 15b. The printer relay 10b may be employed to directly print the character selected by the other five relays 16, or may function to transfer the code .group set up to another group of magnets or selectors provided in Y will thereafter be reset in readiness for the next code group transmitted.

The scanning frequency in cycles per second is equal to the rate of transmission of code groups per second. There is no inertia, mechanical wear, sparking or dust troubles with the electronic distributor of my invention. A greatly increased speed of operation is possible with this system as compared to existing printing telegraphy systems employing mechanical distributors.

I claim:

1. In a signalling system, a receiver for transmitted coded signals; an electronic distributor associated With said receiver responsive to said signals comprising a plurality of conductive targets, means for generating an electron beam, and

-anv electrode for controlling the focusing of said beam; and means for scanning said distributor beam in the vicinity of the receiver targets comprising an oscillator having means controlled by one of said targets for generating an alternating current of frequency substantially equal to the transmitter group frequency.

2. In a signalling system, a receiver for transmitted coded signals; an electronic distributor associated with said receiver responsive to said signals comprising a plurality of conductive targets, means for generating an electron beam, and an electrode for controlling the focusing of said beam; and means for scanning said distributor beam in the vicinity of the receiver targets comprising an impulse excited oscillator having means controlled by one of said targets for generating an alternating current of frequency substantially equal to the transmitter group frequency, and beam deilecting means, the output of said oscillator being connected to said beam deflecting means, and means associated with said electrode for selectively focusing said beam upon said targets in response to said signals.

3. In a signalling system, a receiver for transmitted coded signals; an electronic distributor associated with said receiver responsive to said signals comprising a pluralityy of conductive targets, means for generating an electron beam, and an electrode for controlling the focusing of said beam; means for scanning said distributor beam in the vicinity of the receiver targets comprising an impulse-excited oscillator having means controlled by one of said targets for generating an alternating current of frequency substantially equal to the transmitter group frequency, and beam deflecting means, the output of said oscillator being connected to said beam dei'lecting means, and means for adjusting the phase relation of said oscillator current to control the phase of said beam across said targets; and means for translating the received signals comprising a plurality of amplier units having their inputs individually connected to said receiver targets, and means individually controlled by said amplifier units for creating successive local conditions corresponding to the transmitted coded signals.

4. In a signalling system, a receiver for transmitted coded signals; an electronic distributor associated with said receiver, responsive to said signals comprising a plurality of conductive targets circularly arranged, means for generating an electron beam, and an electrode for controlling the focusing of said beam; andy means for scanning said distributor beam in the vicinity of the receiver targets comprising an impulse excited oscillator having means controlled by one of said targets for generating an alternating current of frequency substantially equal to the transmitter group frequency, and beam deflecting means, and a rotator circuit connecting the output of said oscillator to said beam deflecting means, and means associated with said electrode for selectively focusing said beam upon said targets in response to said signals.

5. In a signalling system, a receiver for transmitted coded signals; an electronic distributor associated with said receiver, responsive to said signals comprising a plurality of conductive targets circularly arranged, means for generating an electron beam, and an electrode for controlling the focusing of said beam; means for scanning said distributor beam in the vicinity of the receiver targets comprising an impulse excited oscillator having means controlled by one of said targets for generating an alternating current of frequency substantially equal to the transmitter group frequency, and beam deilecting means, and a rotator circuit connecting the output of said oscillator to said beam deflecting means; and means for translating the received signals comprising a plurality of amplifier units having their inputs individually connected to said receiver targets, and relay means individually controlled by said amplifier units for creating successive local conditions corresponding to the transmitted code combinations, said electrode being connected to the output of said receiver for focusing said beam upon corresponding targets to selectively actuat said relay means. 6. In a signalling system, a receiver for transmitted coded signals; an electronic distributor associated with said receiver responsive to said signals comprising a plurality of conductive targets clrcularly arranged, means for generating an electron beam, and an electrode for controlling the focusing of said beam; means for scanning said distributor beam in the vicinity of the receiver targets comprising an impulse excited oscillator having means controlled by one of said targets for generating an alternating current of frequency substantially equal to the transmitter group frequency, and beam deilecting means, a rotator circuit connecting the output of said oscillator to said beam deflecting means, and means for adjusting the phase relation of said synchronizing signal to control the phase of said beam across said targets; and means for translating the received signals comprising a plurality of amplifier units having their inputs individually connected to said receiver targets, and relay means individually controlled by said amplier units for creating successive local conditions corresponding to the transmitted code combinations, said electrode being connected to the received signals for focusing said beam upon corresponding targets to selectively actuate said relay means, and means including one of said relay means responsive to said one receiver target for cyclically controlling the resetting operation between said successive local conditions.

WILLIAM G. H. FINCH. 

